Re: [RFC v1] add new io-scheduler to use cgroup on high-speed device
From: Tejun Heo
Date: Tue Jun 04 2013 - 23:03:49 EST
(cc'ing Kent. Original posting at
On Wed, Jun 05, 2013 at 10:09:31AM +0800, Robin Dong wrote:
> We want to use blkio.cgroup on high-speed device (like fusionio) for our mysql clusters.
> After testing different io-scheduler, we found that cfq is too slow and deadline can't run on cgroup.
> So we developed a new io-scheduler: tpps (Tiny Parallel Proportion Scheduler).It dispatch requests
> only by using their individual weight and total weight (proportion) therefore it's simply and efficient.
> Test case: fusionio card, 4 cgroups, iodepth-512
So, while I understand the intention behind it, I'm not sure a
separate io-sched for this is what we want. Kent and Jens have been
thinking about this lately so they'll probably chime in. From my POV,
I see a few largish issues.
* It has to be scalable with relatively large scale SMP / NUMA
configurations. It better integrate with blk-mq support currently
* It definitely has to support hierarchy. Nothing which doesn't
support full hierarchy can be added to cgroup at this point.
* We already have separate implementations in blk-throtl and
cfq-iosched. Maybe it's too late and too different for cfq-iosched
given that it's primarily targeted at disks, but I wonder whether we
can make blk-throtl generic and scalable enough to cover all other
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